#!/usr/bin/env sh

delay=$1
usage='Usage: st [delay_in_milliseconds]\n\nThis utility will toggle sidetone for your primary audio input device.\nDelay argument is optional -- default: 1\n'
# Sanity check
### Set delay to 1 if unspecified
if [ $# -eq 0 ]; then
    delay=1
fi

### Check if pavucontrol is available
if (! type pactl &>/dev/null); then
    printf "ERROR 12: 'pactl' command not found!\n\n  This command is part of PulseAudio Volume Control, which may commonly be found in your distribution's repository as 'pavucontrol'.\n  Please install and try again." >&2
    exit 12
fi

### Check if delay value >1
if [ $delay -lt 1 ]; then
    echo "ERROR 13: Delay can not be less than 1!" >&2
    printf "\n$usage"
    exit 13
fi

### Check if delay value is an integer (no extra characters)
case $delay in
    ''|*[!0-9]*) 
        echo "ERROR 14: Delay value must be an unsigned integer!" >&2 ;
        printf "\n$usage" ;
        exit 14 ;;
esac
# End sanity check


if (pactl list | grep module-loopback) 2>&1 >/dev/null; then
    pactl unload-module module-loopback
    echo "Sidetone: OFF"
    exit 0
else
    pactl load-module module-loopback latency_msec=${delay} >/dev/null || exit 1
    if [ $delay -gt 1 ]; then
        printf "Sidetone: ON\tDelay: ${delay}ms\n"
    else
        echo "Sidetone: ON"
    fi
    exit 0
fi


echo "ERROR 3: We don't know WTF happened!" >&2
exit 3